If peace is at hand in Lebanon, it has been heralded by awesome violence and an unprecedented massing of Israeli war materiel.
Here in Beirut this has raised questions about whether the Israeli government is really prepared to put its faith in the plan for evacuation of the PLO devised by American envoy Philip Habib.
The closer a diplomatic settlement has seemed, the more Israeli jets, tanks, and gunboats have unleashed their destructive might on west Beirut; the more Israeli armor and foot soldiers have filed into the hills around the city; and the more elements of a final assault have fallen into place.
Ironically, it took a US suspension of the Habib peace talks to halt Israeli military action -- and give the talks renewed opportunity.
It was Israel's hard-line tactics that prompted the Reagan administration to intervene forcefully Thursday. Washington suspended the Habib negotiations and an outraged President Reagan told Israeli Prime Minister Menachem Begin that the latest fighting had halted the talks when they were on the verge of success.
By the time Israel responded with yet another cease-fire late Thursday, the Lebanese crisis had come down, in effect, to this: Either the PLO evacuation would proceed posthaste -- or Israeli armed forces would storm the capital.
Israeli pounding of west Beirut was almost constant Wednesday and Thursday. Jets swooped down on the city every 20 minutes, wrecking buildings and vehicles and causing extensive casualties among guerrillas and civilians in west Beirut. Israeli planes, tanks, and naval guns punished virtually all of greater Beirut south of the Corniche Mazra road, which separates the commercial district from the predominantly Palestinian suburbs. West Beirut proper also came under attack.
Fighting in the large pine forest near the city's Hippodrome was especially heavy, and Israeli tanks were slowly advancing and erecting new earthen fortifications there and near Palestinian camps to the south. Returned fire from guerrillas was persistent and caused scattered casualties among Israeli soldiers and Lebanese civilians in east Beirut, but it was nowhere near as fierce as what the Israeli military meted out.
Meanwhile, new Israeli armor, artillery, and infantry were deploying around Beirut and as far north as the port of Byblos. Israeli officers say this buildup is only for the final assault on west Beirut if and when the negotiations should completely founder. They insist it is neither meant for use against Syrians and Palestinians in the Tripoli or Bekaa Valley regions nor to police a PLO evacuation.
But much of the new deployment was high in the rugged Lebanese mountains, many hours away from Beirut. From these positions Israeli forces conceivably could push into northern and eastern Lebanon.
Israeli officers interviewed by the Monitor, however, maintain that the military entanglement in which they have already been caught in Beirut and southern Lebanon is enough of a problem for Israel without venturing further.
''At this point the main concern of the state of Israel is west Beirut,'' Col. Yehiel Ben Zvi, Israel's official Army spokesman in Lebanon, said Aug. 12. ''We are ready to act immediately. Then when we get rid of the terrorists in west Beirut, by agreement or by military operations, we will look at other issues.''
The sustained bombing and shelling of the beleaguered west side of Beirut, the colonel said, was to make sure PLO leaders feel compelled to leave. ''If they don't have the pressure, they will change their minds from one minute to the next.''
Sources close to the PLO and the Lebanese government continued Aug. 12 to say the PLO had every intention of departing. And Israeli leaders -- including military officers -- said that despite the heavy buildup and the sustained attacks on the city they, too, were optimistic.
Details of the Habib plan, however, may take no small amount of negotiating and good faith to hammer out. Mr. Begin has asked Mr. Habib for:
1. A list of all guerrillas and their countries of destination, so that none stay behind.
2. Exclusion of United Nations observers from the proposed international police force, because Mr. Begin feels the UN is anti-Israel.
3. Soldiers other than French soldiers to be the vanguard going into west Beirut because Mr. Begin fears the French might end up shielding an intransigent PLO.
None of these conditions seemed impossible to meet. Of greater concern were matters that might seem arcane to those watching from afar but that, in the complex Lebanese situation, were crucial. These were:
* Could the shaky Lebanese Army actually go into west Beirut, under multinational force supervision, without splintering?
* Could the PLO be assured of protection from the rightist, mainly Christian Phalangists as it departs either by land through Phalangist east Beirut or by sea, from the Phalange-controlled port?
* What would be the fate of the leftist Lebanese groups such as the Nasserite Muribitoun once their ally and sometime protector, the PLO, leaves the scene? Would these factions remain armed?
* Would Palestinian families left behind by the guerrillas be safe? Would they be allowed to join their menfolk in other Arab countries at a later date?
If these questions had been adequately answered, many leaders here were prepared to express optimism about the eventual outcome. But at this writing, there had been no official statement regarding these matters. If the questions have been ignored or glossed over, the Habib plan could break down before it gets started or part way through.
That may be why the Israeli Army, according to Colonel Zvi, has ''intensively reinforced in the past two or three days,'' completing preparations in case Israel decides to storm Beirut.